President Barack Obama leaves a press conference at the conclusion of the 2012 NATO Summit May 21, 2012 in Chicago.

As the candidates try to distinguish themselves from each other, there is one area in which Aaron David Miller of Foreign Policy sees no difference at all. It's foreign policy, and he says that since Sept. 11 the parties have come to a consensus on how America will interact with the rest of the globe.by Aaron David MillerAaron David Miller is a distinguished scholar at the Woodrow Wilson International Center for Scholars. His forthcoming book is titled Can America Have Another Great President?

If Barack Obama is re-elected, he ought to consider making Mitt Romney his new secretary of state. I propose this far-fetched howler not because I'm trying to get into my own Dumb Idea Hall of Fame, or because white-male secretaries of state seem to be going the way of the dodo at Foggy Bottom (we haven't had one since Warren Christopher departed in 1997), or because I believe deeply in bipartisanship. (Although I do; it's been a long time since we've had a secretary of state who was from the opposing party, and it would be great idea.)

I raise the idea to drive home a broader point. Despite his campaign rhetoric, Romney would be quite comfortable carrying out President Obama's foreign policy because it accords so closely with his own.

And that brings up an extraordinary fact. What has emerged in the second decade after Sept. 11 is a remarkable consensus among Democrats and Republicans on a core approach to the nation's foreign policy. It's certainly not a perfect alignment. But rarely since the end of the Cold War has there been this level of consensus. Indeed, while Americans may be divided, polarized and dysfunctional about issues closer to home, we are really quite united in how we see the world and what we should do about it.

Ever wondered why foreign policy hasn't figuredall that prominently in the 2012 election campaign? Sure, the country is focused on the economy and domestic priorities. And yes, Obama has so far avoided the kind of foreign-policy disasters that would give the Republicans easy free shots. But there's more to it than that: Romney has had a hard time identifying Obama's foreign-policy vulnerabilities because there's just not that much difference between the two.

A post Sept. 11 consensus is emerging that has bridged the ideological divide of the Bush 43 years. And it's going to be pretty durable.

Paradoxically, both George W. Bush's successes and failures helped to create this new consensus. His tough and largely successful approach to counterterrorism ? specifically, keeping the homeland safe and keeping al-Qaida and its affiliates at bay through use of special forces, drone attacks, aggressive use of intelligence, and more effective cooperation among agencies now forms a virtually unassailable bipartisan consensus. As shown through his stepped-up drone campaign, Barack Obama has become George W. Bush on steroids.

And Bush 43's failed policies ? a discretionary war in Iraq and a mismanaged one in Afghanistan ? have had an equally profound effect. These adventures created a counter-reaction against ill-advised military campaigns that is now bipartisan theology as well.

To be sure, there are some differences between Romney and Obama. But with the exception of Republicans taking a softer line on Israel and a tougher one on Russia ? both stances that are unlikely to matter much in terms of actual policy implementation ? there's a much greater convergence.

Yes, in the interests of winning votes, Romney will hone a few choice attacks in the campaign to come: "The president is weak and an apologizer, I'm not!" "The president doesn't believe in American leadership, I do!" These tropes, however, are either meaningless or inaccurate, and aren't likely to resonate much with a foreign policy-fatigued public.

Four key principles drive the new post, post-Sept. 11 consensus:

1. Fix Our Broken House: These days, any sentient politician understands that the key to American power abroad is inextricably linked to the state of our union here at home. Whether or not our leaders are prepared to pay the political price to address these domestic problems is another matter. But the talking points seem pretty similar: Build our nation first, not anyone else's. Watch what you're spending abroad, and focus on the five deadly Ds at home ? debt, deficit, dysfunctional politics, decaying infrastructure, and dependence on Middle East hydrocarbons.

Whether it's a Democratic or Republican president, domestic priorities have set the tone for a retrenchment in America's global footprint for years to come. When it comes to risky foreign-policy initiatives, expect politicians to take a long look in the rear-view mirror first.

2. But Defend It: The second core consensus is the need to kill the bad guys abroad before they can kill us, but to do it without invading nations and thus becoming responsible for rebuilding them. Bush 43, for all his other foreign-policy failures, can boast that there were no attacks on the continental United States after Sept. 11, and Obama ? despite a few near misses ? has maintained the record.

Romney would try just as hard. In this environment, no U.S. president ? if presented with reliable and actionable intel ? would have declined to order a hit on Osama bin Laden in Pakistan or anywhere else. Indeed, the president should be careful about getting into a game of "my predator drone is bigger than yours" with Romney. Fighting terrorists is now a truly bipartisan effort.

3. End Wars, Don't Begin Them: Sadly, the dominant question of America's 21st century conflicts so far is not "can we win?" but "when can we leave?" That was the central question that has occupied Obama's decision-making in Iraq and Afghanistan.

And no matter who becomes president in 2012, there's not going to be much enthusiasm for further adventures abroad or trillion-dollar experiments in nation-building. Democrats and Republicans may finally have broken the code: Discretionary wars and interventions require higher standards for success because, well, they're wars of choice. And our leaders need to be cruel and unforgiving about deciding not only how and when to wage them, but also how to get in and out of them if they do.

The new caution is a bipartisan one. President Romney would have steered clear of unilateral intervention in Libya, and been as cautious as Obama (rightly) has been on Syria.(Iran is a special case, which I will address below.)

4. Subcontract, Create a Committee and a Process Whenever Possible: Whoever came up with the term "leading from behind" erred only in the packaging. Wrong choice of words; right idea. America can't save the world by itself, nor should we expect to or be expected to by others. Let's be clear. We can always lead from the front ? into disaster (see: Afghanistan, Iraq) ? and who wants that?

Instead, the greater challenge is how to decide when and how to intervene successfully in a way that's congruent with our interests and resources. Multilateralism and process became dirty words during the George W. Bush years. And, hey, they're not heroic measures. Indeed, they're time-consuming and often messy because they depend on others. But they can be useful, particularly when vital and core American national interests aren't involved. Think Libya, a moderately successful policy run by committee ? or even a messier situation like Syria, where there are no good options, and acting (or not) with others can fill a vacuum until an opportunity for more concerted action presents itself.

It's not only on these core assumptions that the candidates share a broad agreement. These principles translate into specific policies where it would be tough to tell the difference between a Romney and an Obama presidency:

Iran: Sorry, I just don't see any significant difference between the way Obama is handling Iran's nuclear program and the way Romney might as president. And that's because there's seems to be an inexorable arc to the Iranian nuclear problem. If by 2013 sanctions and negotiations don't produce a sustainable deal and Iran continues its quest for a nuclear weapon, one of two things is going to happen: Israel is likely to strike, or we will.

If it's the former, both Obama and Romney would be there to defend the Israelis and manage the mess that would follow. Both would be prepared to intercede on Israel's behalf if and when it came to that. As for a U.S. strike, it's becoming a bipartisan article of faith that the United States will not permit Iran to acquire a nuclear weapon. And both men are prepared to use military strikes against Iran's nuclear sites as a last resort, even if it only means a delay (and that's what it would mean) in Iran's quest for nukes.

Freedom Agenda: The bloom went off this rose in George W. Bush's administration. The Arab Spring has turned into a long cold winter ? the prospects for the quick and easy rise of democracies in the Middle East are slim to none. A Romney administration might produce a tougher tone in defense of freedom (without any meaningful action) and perhaps more negative rhetoric about Islamists, but would also confront the same bad options and limited leverage Obama has now. On Egypt, Syria, Bahrain, Yemen, and anywhere else the United States is unable to direct the domestic politics in distant lands, Romney would likely adopt much the same approach as the current administration.

Diplomatic Engagement: Had you listened to Obama in 2009, you might very well have concluded that he was out to change the world through engagement and diplomacy. But that was then. Obama has learned quite a bit, and appears to have come much closer to the tougher-minded Romney view on the merits of engaging Hugo Chavez, the Kim regime in North Korea, the mullahs in Tehran, and Bashar Assad in Syria. Conspicuously absent from this list of leaders that Obama has seemingly written off is Vladimir Putin, who appears to be an integral part of the White House's Iran strategy.

Romney has taken a much tougher line on Russia and China. Still, the realities of governing would invariably soften the Romney campaign line that Russia is public enemy No. 1 and that China is a currency manipulator.

Israel: Paradoxically, theone issue where Romney and Obama might actually differ is on the most bipartisan one of all ? Israel. Romney's views on Israel are guided more by his gut instincts (see Bush 43) than Obama, whose view of the Israelis is colder and more calculating.

The issue isn't support for Israel's security ? both would be committed to that. It's that damn peace process, which keeps turning up like a bad penny. Obama wants progress, and sees Prime Minister Benjamin Netanyahu as largely responsible for the lack of it. He may want to push some bold initiative in a second term, but it won't be so easy to do. For Romney, the peace process isn't going to be a priority unless the Israelis and Palestinians ? through violence or diplomacy ? make it one.

The bottom line? The new consensus is that the world's a more challenging place than ever, and both Democrats and Republicans are learning that we can't control it. (Of course, we never did.) That doesn't mean that the United States cannot lead or succeed in protecting its interests, it just means its leaders need to be more disciplined about how and when to project American power.

The new divide on foreign policy is clear ? and I, for one, am ecstatic about it. It's not between left and right, liberal or conservative, or Republican or Democrat. It's between making decisions that are smart, on the one hand, or dumb on the other. And I'm hoping that the next president ? whoever he is ? knows exactly which side America wants to be on.